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-rw-r--r--include/linux/fd.h8
1 files changed, 7 insertions, 1 deletions
diff --git a/include/linux/fd.h b/include/linux/fd.h
index b6bd41d2b46..f5d194af07a 100644
--- a/include/linux/fd.h
+++ b/include/linux/fd.h
@@ -15,10 +15,16 @@ struct floppy_struct {
sect, /* sectors per track */
head, /* nr of heads */
track, /* nr of tracks */
- stretch; /* !=0 means double track steps */
+ stretch; /* bit 0 !=0 means double track steps */
+ /* bit 1 != 0 means swap sides */
+ /* bits 2..9 give the first sector */
+ /* number (the LSB is flipped) */
#define FD_STRETCH 1
#define FD_SWAPSIDES 2
#define FD_ZEROBASED 4
+#define FD_SECTBASEMASK 0x3FC
+#define FD_MKSECTBASE(s) (((s) ^ 1) << 2)
+#define FD_SECTBASE(floppy) ((((floppy)->stretch & FD_SECTBASEMASK) >> 2) ^ 1)
unsigned char gap, /* gap1 size */